FDA Approves New Parkinson's Drug Targeting Different Receptors

The U.S. Food and Drug Administration (FDA) has approved tabepedon, developed by AbbVie, for the treatment of Parkinson's disease in adults. This new daily pill, to be marketed as Juvmo, represents a different approach to managing the condition, which affects over 11 million people globally.

Unlike most existing Parkinson's treatments that focus on supplementing dopamine or mimicking its effects on D2 receptors, tabepedon targets D1 and D5 receptors. These receptors are primarily involved in voluntary movement. Previous attempts to target these receptors were hampered by rapid drug breakdown and severe side effects like involuntary movements. Tabepedon is designed to be more stable in the body and offers partial receptor activation, aiming to improve motor function without overstimulation.

Clinical trials involving over 800 patients showed significant improvements in movement and daily functioning compared to placebo. In one trial, 45% of patients on tabepedon reported substantial improvement versus 12% on placebo. A separate trial for patients with advanced Parkinson's demonstrated that adding tabepedon provided an extra hour of good function daily without increasing involuntary movements.

Israeli medical centers participated in the trials, with Professor Tanya Gorovitz of Tel Aviv's Ichilov Medical Center noting tabepedon's potential as a new class of dopamine agonists that could reduce side effects like dyskinesia and impulse control issues. She expressed hope for its swift availability in Israel.

Common side effects observed in trials included nausea, dizziness, and headaches, affecting about a tenth of participants in a longer-term study. While some patients discontinued the drug during trials, side effects common to older Parkinson's medications, such as somnolence and compulsive behaviors, were rare. However, experts caution that longer-term studies are needed to fully assess the drug's efficacy and safety compared to existing treatments, and it remains a symptomatic treatment, not a disease-modifying one.